1. Field
The following description relates to a 3-dimensional (3D) face recognition technology, and more particularly, to an apparatus and method for generating a 3D face model using a mobile device.
2. Description of Related Art
A 3-dimensional face model which is widely used in various areas, such as art, films, and animations, is generated using laser scanning devices, or by analyzing a geometrical correlation between multi-view images obtained through multiple cameras placed around an object. These conventional methods require a dedicated space, a specific environment and equipment, and so cannot be utilized by general users who want to produce their 3D face model at low cost.
Recently, a method has been suggested which sequentially obtains images of an object from various directions using a camera built in a mobile device that is moving around the object, and produces a 3D model based on the obtained images that are regarded as simultaneously acquired multi-view images.
The aforesaid method for generating a 3D model based on multi-view images needs clear images that accurately show the texture of an object whereby a sufficient amount of feature point information can be extracted. 3D reconstruction is generally carried out based on multi-view images which are acquired by multiple multi-view cameras at the same time point on the time axis, whereas in the above method, facial images are subsequently obtained by a single camera which substitutes for the multi-view cameras and hence the user must capture the images with a minimal motion. If the user wants to capture real-time images of him/herself, the user needs to use a front facing camera on the same surface of the display of a mobile device. The user can capture such images in a still image mode or a video mode.
In the video mode, the user can continuously capture facial images from different angles while moving the camera, but the motion of the camera may cause the images to be blurry, and, by the nature of camera hardware, image quality of the video mode is generally lower than that obtained in the still-image mode.
Thus, in order to capture a clear image, the user needs to be ready for capturing at each direction while moving the camera and then take a still image. In this case, if the user presses a button inside or outside of a screen with a finger to capture the image, the mobile device may be shaken, and, in turn, the image quality is degraded.
When the user vocally instructs the image capturing using a voice interface function, the user's face may move. If the user captures images at specific time intervals using a timer, the user cannot have sufficient time to adjust the position and orientation of the mobile device at each time point.
As described above, the conventional technologies for creating a 3D face model based on multi-view images that are sequentially acquired by a single mobile device do not address the aforementioned problems, and nor do they suggest an approach for obtaining clear multi-view images of a user's face. Therefore, these technologies are too limited to be applied to the creation of 3D face model.